Optically functional multilayer structure and related method of manufacture

ABSTRACT

An integrated optically functional multilayer structure includes a flexible, substrate film arranged with a circuit design including at least a number of electrical conductors preferably additively printed on the substrate film; a light source provided upon a first side of the substrate film to internally illuminate at least portion of the structure for external perception; an optically transmissive plastic layer, produced upon the first side of the substrate film, said plastic layer at least laterally surrounding, the light source, the substrate film at least having a similar or lower refractive index therewith; and a reflector design comprising at least one material layer, said reflector design being configured to reflect, the light emitted by the light source and incident upon the reflector design.

FIELD OF THE INVENTION

The present invention relates in general to functional, integratedstructures incorporating various functional features such as electronic,mechanical or optical elements. In particular, however not exclusively,the present invention concerns the provision of such structurescomprising at least one or more optoelectronic light sources.

BACKGROUND

There exists a variety of different stacked assemblies and multilayerstructures in the context of different functional ensembles e.g., in thefield of electronics and electronic products. The motivation behind theintegration of functionalities involving e.g., electronics, mechanicalor optical features may be as diverse as the related use contexts.Relatively often size savings, weight savings, cost savings, or justefficient integration of components is sought for when the resultingsolution ultimately exhibits a multilayer nature. In turn, theassociated use scenarios may relate to product packages or casings,visual design of device housings, wearable electronics, personalelectronic devices, displays, detectors or sensors, vehicle interiors,antennae, labels, vehicle electronics, etc.

Electronics such as electronic components, ICs (integrated circuit), andconductors, may be generally provided onto a substrate element by aplurality of different techniques. For example, ready-made electronicssuch as various surface mount devices (SMD) may be mounted on asubstrate surface that ultimately forms an inner or outer interfacelayer of a multilayer structure. Additionally, technologies fallingunder the term “printed electronics” may be applied to produceelectronics directly and additively to the associated substrate. Theterm “printed” refers in this context to printing techniques capable ofproducing electronics/electrical elements from the printed matter,including but not limited to screen printing, flexography, and inkjetprinting, through a substantially additive printing process. The usedsubstrates may be flexible, stretchable and printed materials organic,which is however, not always the case.

Furthermore, the concept of injection molded structural electronics(IMSE) involves building functional devices and parts therefor in theform of a multilayer structure, which encapsulates electronicfunctionality as seamlessly as possible. Characteristic to IMSE is alsothat the electronics is commonly manufactured into a true 3D(non-planar) form in accordance with the 3D models of the overall targetproduct, part or generally design. To achieve desired 3D layout ofelectronics on a 3D substrate and in the associated end product, theelectronics may be still provided on an initially planar substrate, suchas a film, using two dimensional (2D) methods of electronics assembly,whereupon the substrate, already accommodating the electronics, may beformed into a desired three-dimensional, i.e. 3D, shape and subjected toovermolding, for example, by suitable plastic material that covers andembeds the underlying elements such as electronics, thus protecting andpotentially hiding the elements from the environment. Further layers andelements may be naturally added to the construction.

Optical features and functionalities to be provided in theafore-discussed integrated structures may include a number of lightsources that are intended to illuminate e.g., selected internals of thestructure or the environment of the structure. Illumination may havedifferent motives per se, such as decorative/aesthetic or functional,such as guiding or indicative, motives.

For example, in some use scenarios the environment should be lit forincreased visibility in gloomy or dark conditions, which may, in turn,enable trouble-free performing of various human activities typicallyrequiring relatively high lighting comfort, such as walking, reading, oroperating a device, to take place. Alternatively, the illumination couldbe applied to warn or inform different parties regarding e.g., thestatus of the structure or a related host device, or a connected remotedevice, via different warning or indicator lights and e.g., associatedgraphics. Yet, the illumination might yield the structure or its host adesired appearance and visually emphasize its certain areas or featuresby a desired color or brightness. Accordingly, the illumination couldalso be applied to instruct a user of the structure or its host deviceabout e.g., the location of different functional features such as keys,switches, touch-sensitive areas, or other UI (user interface) featureson the device surface, or about the actual function underlying theilluminated feature.

Various challenges may commonly emerge in the described and otherillumination applications and use scenarios, however.

For example, undesired light bleed or leakage out of the structure orbetween different internal volumes and areas thereof may easily causeboth functional and aesthetic issues not forgetting transmission lossesfrom the standpoint of a desired optical path and original illuminationtarget, as being easily comprehended by a person skilled in the art.Yet, the perceivability of light sources themselves is one potentialfurther issue. In some applications, the light sources should preferablyremain hidden or only weakly or occasionally exposed.

Additionally, achieving sufficient resolution and in many cases, alsodynamic or adaptive, control of internally transmitted and ultimatelyoutcoupled light in terms of e.g., illuminated surface area shape, size,or location may at least occasionally turn out difficult with highlyintegrated structures. In various solutions, controlling orspecifically, improving e.g., the uniformity of light over itsoutcoupling surface, which may sometimes also span considerably largeareas in relation to the overall dimensions of the structure or itsselected surface, has been previously found burdensome. The same appliesto spatial control of illumination and light outcoupling also moregenerally. This may be an important issue e.g., when the surfacecontains e.g., an icon or symbol to be evenly lit to indicate to aviewer external to the structure that a device functionality or statusassociated with the icon or symbol is active, for example. Simplyharnessing several light sources to more effectively lit up a jointtarget area or feature, such as an icon, may still cause illuminationhot spots and additional leakage while also requiring more, oftenprecious, power and space. Obtaining decent mixing of brightness orcolors may also be challenging and require a relatively long distancebetween the light source(s) and area or feature to be illuminatedtherewith especially in large area illumination applications, which addsto the size of the structure required or reduces the area that can beilluminated with proper mixing performance.

Still, some, in many ways generally favourable, light sources such ase.g., high-power LEDs may consume somewhat remarkable power (easily inthe order of magnitude of about 1 watt or more) and eventually end up sohot that they degrade or break. They may also damage adjacentheat-sensitive elements such as plastic substrates.

Adding multiple, potentially complex light guiding, incoupling,outcoupling, limiting or generally processing elements into thestructure has, in turn, its own drawbacks such as increased spaceconsumption, weight and other design constraints. Maintaining theoptical performance of the structure high, with reference to e.g., lowleakage, loss, and similar objectives, may easily further limit theshape of the structure or included elements to ones otherwisesub-optimum in their intended use case.

Yet, if the optical features such as illumination features are to becombined with other features in the structure, the other features maynegatively affect the lighting performance due to their shadowing ormasking effect, for example, and occasionally also the optical featuresmay prevent or complicate the implementation of the other features dueto e.g., space constraints faced.

Manufacturing process-wise the adoption of various optical features inthe structures may increase besides the overall process complexity alsothe amount of faced complications due to the added features' mutual(in)compatibility or (in)compatibility with the remaining materials andfeatures as well as related process phases, considering e.g.,overmolding, resulting in an increased fail rate/reduce yield. Forexample, if a material associated with a lower melt temperature (e.g.polymethyl methacrylate, PMMA) is utilized together with a higher melttemperature molding material (e.g. polycarbonate, PC), features printedor otherwise established on the lower melt temperature material maydegrade or wash out during molding.

SUMMARY

The objective of the present invention is to at least alleviate one ormore of the drawbacks associated with the known solutions in the contextof optically functional integrated structures and related methods ofmanufacture.

The objective is achieved with various embodiments of an integrated,functional multilayer structure and a related method of manufacture forproviding the multilayer structure.

According to one aspect, an integrated optically functional multilayerstructure comprises

-   -   a flexible, optionally 3D-formable and thermoplastic, substrate        film, optionally being a single-layer or multilayer film,        arranged with a circuit design comprising at least a number of        electrical conductors, such as traces and/or contact pads,        preferably additively printed on the substrate film;    -   a light source provided upon a first side of the substrate film        to internally illuminate at least portion of the structure for        external perception;    -   an optically transmissive plastic layer, optionally of        thermoplastic material such as polycarbonate among many other        feasible material options, produced, preferably molded, upon the        first side of the substrate film and preferably upon the light        source, said plastic layer at least laterally surrounding,        optionally also at least partially covering, the light source,        the substrate film optionally comprising material or material        layer same as that of the plastic layer or at least having a        similar or lower refractive index therewith; and    -   a reflector design comprising at least one material layer        optionally including electrically conductive material, said        reflector design being configured to reflect the light emitted        by the light source and incident upon the reflector design        preferably towards the plastic layer.

In a further aspect, a method for manufacturing an integrated opticallyfunctional multilayer structure, comprises:

-   -   obtaining a flexible, optionally 3D-formable and thermoplastic,        substrate film, optionally a multilayer film, provided with a        circuit design comprising at least a number of electrical        conductors, such as traces and/or contact pads, preferably        additively produced such as printed on the substrate film;    -   arranging at least one light source upon a first side of the        substrate film;    -   producing, optionally through molding or 3D printing, an        optically transmissive plastic layer upon the first side of the        substrate film and preferably upon said at least one light        source, said plastic layer at least laterally surrounding or        neighbouring, optionally also at least partially covering, the        light source, said plastic layer thus potentially at least        partially embedding the light source; and    -   providing, optionally including printing, coating, laminating or        molding, a reflector design comprising at least one material        layer, optionally comprising a stack of material layers and/or a        layer of preferably electrically conductive and/or metallic        material, said reflector design being configured to reflect,        optionally dominantly specularly, the light emitted by the at        least one light source and incident upon the reflector design,        preferably towards the plastic layer.

The present solution yields different advantages over a great variety ofpreviously applied solutions, naturally depending on each embodimentthereof.

For example, incoupling, transmission and (out)coupling of light may beeffectively controlled and related optical efficiency and various othercharacteristics of interest, such as achieved illumination uniformity,optimized in a concerned optical structure by clever, jointconfiguration of the included materials and elements such light sources,with respect to e.g., their mutual positioning, orientation, dimensionsand other characteristics. The solution also suits large areaillumination applications particularly well and facilitates reducing orkeeping the number of required light sources low, which has its clearadvantages in terms of space savings, power consumption, structural andmanufacturing complexity, weight, etc.

E.g., embedded mirror type reflectors may be arranged opposite or nextto the light sources, using e.g. conductive, typically metallicmaterials or a multitude of varying refractive index layers, to enableefficient transmission and control of light within the structure. Yet,total internal reflection (TIR) capable interfaces may be additionallyconfigured to supplement and, for example, stack with mirror reflectorsfor even more sophisticated and flexible control of light conveyance.

The “hidden until lit” effect may also be produced. For instance,graphical symbols provided in the structure, various components, ore.g., conductive traces can be obscured from external visual perceptionuntil a light source intended and targeted to illuminate them isactivated.

Manufacturing-wise printing and other cost-efficient, flexible andversatilely controllable methods, such as various molding and coatingtechniques may be cleverly applied to manufacture desired features inaddition to the use of ready-prepared elements such as films,components, or modules.

By properly configuring the light source(s) and e.g., the suggestedreflector design, also mixing characteristics of light on theoutcoupling surfaces along the transmissive plastic layer and the outersurface of the structure in general may be enhanced and thus a so-calledmixing distance needed for achieving the desired mixing performancereduced.

Optical elements such as outcoupling elements may be integrally andmonolithically formed in other elements such as material layersadvantageously by locally deforming the associated materials, whichprovides very efficient optical solutions as well as yields space,material, and weight savings in addition to simplifying the structureand potentially also the manufacturing process among other benefits. Forexample, mirror effect provided by the reflector design may be locallydestroyed to establish a light outcoupling element from the deformedportion, or material(s) at a TIR-enabling interface could be similarlytreated to locally alter the interface's properties for enhancedscattering and/or interfering TIR, for instance.

Adhesion between materials may be improved and e.g., wash-out issues maybe reduced by utilizing multiple layers or multilayer elements so thatthe materials neighbouring the typically molded transmissive layer areselected so as to better survive molding and other processes as well asalso attach to each other or the transmissive layer securely. Forexample, optionally co-extruded multilayer film(s) such as PC/PMMAfilm(s) could be used in a stack structure over and/or below thetransmissive layer comprising e.g., PC resin then injection molded orotherwise produced on the PC layer of the multilayer film or between thePC layers of two multilayer films. Yet, also e.g., printed outcouplingelements could be provided on the PC surfaces with standard and manyways advantageous PC surface inks. In addition, using a co-extrudedmultilayer films reduces adhesion issues between different materiallayers as the adhesion gained from the film co-extruding process isexcellent. Different co-extruded material combinations with even betterrefractive index differences can be utilized.

The suggested multilayer may be modular and put together using aplurality of mutually different and/or similar modules providingdifferent features to the aggregate structure. For instance, IMSE pieceor cell type modules, which are preferably shaped (e.g.hexagonal/honeycomb cell) so that they can be fixed to each otherstraightforwardly, like the pieces of a puzzle, may be utilized. Somemodule(s) may contain more features or functionalities, more complexfunctionalities, harder to implement functionalities, or functionalitiesof several types such as general electronics and/or optoelectronics suchas light sources, while some other module(s) may be simpler and containmainly e.g., passive optical (transmissive material, reflector, mask,etc.) or other features conveniently manufacturable and usable forscaling the size of the structure, for example. The modules may supportsnap-fit joints or crimp fixing for easy mutual fixing, for example.Besides a modular single structure, several multilayer structures may bejoined, optionally stacked, together to form even larger ensembles.Accordingly, modularity may be cleverly provided on different levels andresolutions.

Different embodiments of the present invention may be versatilelyutilized and included in different applications, e.g., in electronic orelectronics-containing appliances including but not limited tocomputers, tablets, smartphones, other communication devices, wearables,av equipment, optical devices, domestic appliances, vehicles, displays,panels, medical devices, smart clothing, furniture, pieces of art, etc.

Various additional utilities different embodiments of the presentinvention offer will become clear to a skilled person based on thefollowing more detailed description.

The expression “a number of” may herein refer to any positive integerstarting from one (1).

The expression “a plurality of” may refer to any positive integerstarting from two (2), respectively.

The terms “first” and “second” are herein used to distinguish oneelement from other element(s), and not to specially prioritize or orderthem, if not otherwise explicitly stated.

The exemplary embodiments of the present invention presented herein arenot to be interpreted to pose limitations to the applicability of theappended claims. The verb “to comprise” is used herein as an openlimitation that does not exclude the existence of also un-recitedfeatures. The features recited in various embodiments and e.g.,dependent claims are mutually freely combinable unless otherwiseexplicitly stated.

BRIEF DESCRIPTION OF FIGURES

Selected embodiments of the present invention are illustrated by way ofexample, and not by way of limitation, in the figures of the appendeddrawings.

FIG. 1 illustrates various features and aspects of the present inventionvia an embodiment of a multilayer structure in accordance therewith.

FIG. 2 illustrates a further applicable configuration of the reflectordesign in different embodiments of the present invention.

FIG. 3 illustrates a further applicable configuration of the reflectordesign in different embodiments of the present invention.

FIG. 4 depicts possible provision of holes in the reflector design andpotential configuration of further layers in the optical path for lightoutcoupling from the structure.

FIG. 5 illustrates an embodiment where outcoupling elements havearranged on the plastic layer.

FIG. 6 illustrates an embodiment incorporating an embedded circuit boardfor hosting at least one light source and potentially furtherelectronics as well as a reflector design including a parabolicreflector surface.

FIG. 7 illustrates another potential embodiment involving a parabolicreflector surface and shape.

FIG. 8 illustrates an embodiment of an illumination ensemble including aplurality of multilayer structures discussed herein.

FIG. 9 illustrates an embodiment wherein a lighting module is includedin the structure, comprising at least one light source on a circuitboard further potentially hosting additional electronics or optics.

FIG. 10 is a flow diagram of an embodiment of a method in accordancewith the present invention.

FIG. 11 illustrates an embodiment with multiple light sources andrelated control circuitry included in the structure.

FIG. 12 illustrates an embodiment including a bend in the plastic layer.

FIG. 13 illustrates an alternative configuration of material layers ofthe multilayer structure, wherein the reflector design, such as materiallayer(s) thereof, may at least locally neighbor the plastic layer.

FIG. 14 illustrates different options and configurations for lightoutcoupling.

FIG. 15 illustrates an embodiment of the multilayer structure furtherincorporating additional functionality such as touch or gesture sensing.

DETAILED DESCRIPTION OF SOME EMBODIMENTS

FIG. 1 generally illustrates, at 100, via a cross-sectional sketch, anembodiment of a multilayer structure in accordance with the presentinvention.

The multilayer structure includes at least one substrate film 102, whichis preferably of flexible and 3D-formable (3D-shapeable) material, suchas thermoformable (plastic) material. As being comprehended by a personskilled in the art, instead of a single, optionally monolithic film 102,there could be a multilayer and/or multi-section construction type film102 a with mutually different layers at least in places, for instance,including also a hosting layer for the electronics. Such multilayer film102 a could manufactured by co-extruding, for example, as a part of anembodiment of a method contemplated hereinlater.

Item 108 refers to at least one, preferably also thermoplastic while atleast optically transmissive layer preferably provided by molding uponthe substrate film 102. Optionally, the layer 108 may have been producedessentially between the substrate film 102 and possible furtherelement(s) or generally, material layer(s), such as at least one furtherlayer or film different from or similar to the film 102, for example.Item 108 may alternatively refer to a plurality of stacked, preferablystill thermoplastic and/or integrated, layers that may have beenoptionally produced by multi-shot molding. The layer 108 should be ableto convey light at least having regard to selected wavelengths such assubstantially all or selected wavelengths of visible light, or generallyat least part of the wavelengths emitted by the included lightsource(s), which typically while not necessarily include visiblewavelengths.

The layer 108 comprises a first side and a related first surface 108 athat may be targeted towards the use environment of the structure ande.g., a user 113 of the structure located in such environment, dependingon the application. Yet, the layer 108 comprises an opposite second sideand associated second surface 108 b essentially facing at least oneinstance of the film 102 and potentially a host device or structure, forinstance. In alternative embodiments, however, the surface 108 b may bethe one that essentially faces the use environment and e.g., usertherein instead of or in addition to the surface 108 a.

As the layer 108 is indeed supposed to convey or guide light, it shallcomprise optically at least translucent, optionally substantiallytransparent, material, wherein the optical transmittance of the overallthermoplastic layer may in some use scenarios preferably be at least50%, but the desired transmittance may indeed radically differ betweenall possible use scenarios. In some embodiments at least about 80% or90% transmittance could be preferred for maximizing the light outputfrom the structure and low losses, while in some other scenarios lowerfigures could be quite sufficient if not even advantageous, if e.g.,light leakage related issues are to be minimized. The transmittance maybe defined or measured in a selected direction, e.g., main direction oflight propagation and/or in a transverse direction (i.e., thicknessdirection) to the surface of the substrate film 102, having regard tothe wavelengths of interest, typically including visible wavelengths asdiscussed above.

Suitable translucency or optical attenuation of the layer 108 could insome embodiments be reached by employing scattering elements such asparticles in the used material, for example. When the amount ofscattering elements is increased, scattering/diffusion and half powerangle, as one possible measurable indicator, are increased as well whileluminous transmission through the layer will generally decrease.Correspondingly, increasing layer thickness generally increasesscattering/diffusion properties such as the half power angle anddecreases transmission.

In terms of applicable materials, the layer 108 may generally comprise,for example, at least one material selected from the group consistingof: polymer, organic material, biomaterial, composite material,thermoplastic material, thermosetting material, elastomeric resin, PC,PMMA, ABS, PET, copolyester, copolyester resin, nylon (PA, polyamide),PP (polypropylene), TPU (thermoplastic polyurethane), polystyrene (PS orGPPS, general-purpose-polystyrene), TPSiV (thermoplastic siliconevulcanizate), and MS resin.

The substrate film 102 may optionally comprise material or materiallayer same as that of the layer 108 or at least having a similar orlower refractive index therewith. Accordingly, the resulting interface102, 108 may be made optically transparent or enabling a total internalreflection (TIR) type function, respectively, for light arriving at theinterface from withing the layer 108.

In some embodiments, tinted or more strongly colored resin as thematerial of layer 108 may provide a feasible option for limitingundesired light leakage within and outside the structure 100 to closeelements or generally distances, and hide the internals such as lightsource 104 or other circuitry from external perception. Originallyoptically substantially clear base material such as PC or other plasticresin could be thus doped with a colored masterbatch. In many usescenarios wherein the structure 100 should be only e.g., few millimetersor a centimeter thick in total, whereupon the thermoplastic layer 108should be even thinner, using about 2-4 mm, such as 3 mm, thick layer ofplastic resin provided with a selected masterbatch (e.g. white ordesired selective wavelength resin, optionally also e.g. IR (infrared)resin that might find use e.g., IR remote control applications) in adesired concentration (e.g. let-down ratio of about 1%) for establishingthe layer 108, may provide quite satisfying results. Generally, in manyembodiments in the context of the present invention, a feasible let-down(dosing or doping) ratio is indeed about 5%, 4%, 3%, 2%, 1% or less. Forexample, suitable industrial grade masterbatches for the purpose areprovided by Lifocolor™. A so-called “hidden until lit” effect may beachieved for the light source 104 or other features included in thestructure 100, for instance, by adding translucent, e.g. a selectedcolor exhibiting, masterbatch in the injection molded base resinconstituting the layer 108.

Item 124 refers to an overcoat at least partially covering a lightemitting portion of the light source, said overcoat layer comprisingoptically transmissive material optionally having a higher refractiveindex than the plastic layer.

The overcoat 124 may include encapsulant, glob top or other conformalcoating, such as a Illumabond™ or Triggerbond™ for light shaping orother processing, protecting and/or securing purposes, for instance. Theused substance may be dispensed on top of selected circuitry such as thelight source 104 or other electronics included in the structure. Thesubstance may be substantially clear (transparent), for example.Alternatively, it could be colored and/or translucent. In someembodiments, a specific optical function or feature such as a lens maybe provided by the encapsulant. The lens could be diffusive, Fresnel ore.g., collimating, for example. Additionally or alternatively, apre-made lens or generally optical component is possible to include inthe structure as well, either on the surface or embedded.

The substrate film 102 and/or further film(s) or generally materiallayer(s) included in the multilayer structure may comprise at least onematerial selected from the group consisting of: polymer, thermoplasticmaterial, electrically insulating material, PMMA (Polymethylmethacrylate), Poly Carbonate (PC), flame retardant (FR) PC film, FR700type PC, copolyester, copolyester resin, polyimide, a copolymer ofMethyl Methacrylate and Styrene (MS resin), glass, PolyethyleneTerephthalate (PET), carbon fiber, organic material, biomaterial,leather, wood, textile, fabric, metal, organic natural material, solidwood, veneer, plywood, bark, tree bark, birch bark, cork, naturalleather, natural textile or fabric material, naturally grown material,cotton, wool, linen, silk, and any combination of the above.

Depending on the embodiment in question, the substrate film 102 and/orfurther film(s) or layers potentially included in the structure maycomprise or be of optically substantially transparent or at leasttranslucent material(s) having regard to the wavelengths of interest,such as visible light, with associated optical transmittance of about80%, 90%, 95%, or more, for example. This may be the case especiallywhen the substrate film 102 is configured in the structure 100 so as toeffectively convey or pass light emitted by the light source 104. Yet,in some embodiments the used substrate film 102 could be substantiallyopaque, black and/or otherwise exhibitive of dark colour, to blockincident light from passing through it (mask function).

The thickness of the film 102 and optionally of further film(s) orlayer(s) included in the structure 100 may vary depending on theembodiment; it may only be of few tens or hundreds of a millimeter, orconsiderably thicker, in the magnitude of one or few millimeter(s), forexample.

The thickness of the layer 108 may also be selected case-specificallybut thicknesses of few millimeters, such as about 3-5 millimeters, maybe applied. In some embodiments, only about 2 millimeter thickness orless, potentially only e.g., few tenths of a millimeter, could besufficient if not optimum, while in some other embodiments the thicknesscould be considerably more as well, e.g. about 1 cm or more at least inplaces. The thickness may indeed locally vary. The layer 108 mayoptionally comprise recesses or internal cavities for light guiding,processing, and/or thermal management purposes, for instance, inaddition to accommodating various elements such as electronic or opticalelements.

The film 102, the layer 108 as well as further layers such as films,coatings, etc. of the structure may be essentially planar (width andlength greater, e.g., different in the order of magnitude, than thethickness). The same generally applies also to the overall structure asillustrated in the figs even though also other, non-planar shapes arefully feasible.

Item 104 refers to a light source preferably of optoelectronic type. Thelight source 104 may be or comprise a semiconductor, a packagedsemiconductor, a chip-on-board semiconductor, a bare chip,electroluminescent and/or a printed type light source, preferably a LED(light-emitting diode) or OLED (organic LED). The light source 104 maybe of top-shooting and bottom installed, of or side-shooting type.Still, multi-side shooters or bottom-shooters may be utilized dependingon the characteristics of each particular use case.

Still packaging-wise, the light source 104 could be optionally offlip-chip type. In some embodiments, the light source may containmultiple (two, three, four, or more) light-emission units such as LEDspackaged or at least grouped together. For example, a multi-color orspecifically RGB LED of several LED emitters could be provided within asingle package.

The light source 104 is provided, such as fabricated (optionally printedwith reference to e.g., OLED) or, in the case of at least partiallyready-made component, mounted on the substrate film 102, preferably on afirst side 102 f and associated surface thereof, which faces thetransmissive layer 108 instead of the opposite second side 102 s andsurface of the film 102. Yet, additional host layer(s) such as films maybe included in the structure for accommodating further elements such aslight sources or other electronics. For mounting, e.g., adhesive(conductive or non-conductive) may be generally applied.

The light source 104 may be at least partially embedded in the materialof the layer 108 during overmolding or otherwise preparing of the layer108 thereon.

The layer 108 may include one or more light outcoupling areas 112 on anyside of the layer 108, such as first 108 a or second 108 b side, throughwhich the light originally emitted by the light source 104, incoupledinto and propagated within the layer 108 is to be outcoupled to thesurrounding layer(s) and/or the environment. The light source 104 may bepositioned as desired having regard to the respective outcouplingarea(s) 112. The source 104 may be located close to an area 112 so thateven a related direct optical path, without reflections, is availablefrom the emission surface(s) of the source 104. Alternatively andperhaps more commonly, the source 104 is a located aside and fartheraway from the associated outcoupling area(s) (e.g., out of LOS,line-of-sight, from the area or external environment adjacent the area)due to a variety of reasons, which may include hiding or masking thesource 104 better from external perception or enhancing the uniformityof illumination (e.g., brightness and/or color(s)) on the area(s) 112 byletting the light emitted by the source 104 to propagate within thelayer 108 and at neighbouring layers or material interfaces, primarilyor also by reflections, for a longer distance and period in favour ofimproved mixing, for example. FIG. 1 shows only a single light source104 for improved clarity, and in many embodiments one source 104 mightbe sufficient if not advantageous, but as being easily comprehended by aperson skilled in art, there are countless embodiments e.g., in thefield of large area illumination that might benefit from includingseveral sources 114 on the same or different substrates (and utilizingshared or separate transmissive layer(s) 108 and/or reflector design(s)110) in the structure, either having at least partially joined orseparate outcoupling area(s) 112 associated with them, affecting thepositioning and orientation of the light sources 104.

Item 106 refers to a circuit design in the form of electrical,optionally additively produced such as screen printed or otherwiseprinted, conductors such as traces and/or contact pads, which mayoptionally further act as thermal conductors. The conductors may be usedfor power and data transfer purposes, for example, between the elementsof the structure 100 and/or with external elements. The circuit design106 may provide control signal and power to the light source 104 from acontroller and power circuit(s), respectively, among other uses. Thecircuit design 106 may connect to an external device via e.g., wiring-or connector-containing exterior surface or edge of the structure 100.Additionally or alternatively, wireless connectivity may be appliedbased on e.g., electromagnetic or particularly, inductive coupling amongother options.

The light source 104 may be emissive as indicated by the dotted lines104 a (top shooting), 104 b (side shooting) extending from the source104 into the transmissive layer 108.

Item 110 and sub-items 110 a, 110 b, 110 c (see FIG. 2 ) refer to areflector design, which may also be of single-part or multi-part(multi-portion) construction. Two or more parts of the multi-partconstruction solution do not have to physically directly connected asthey may reside on the opposite sides 108 a, 108 b of the layer 108, forinstance or otherwise separated by a distance. Yet, any of the parts, orportions, may include one or more material layers e.g., as stacked, astheir constituent elements.

Accordingly, the reflector design 110 comprises least one materiallayer. The reflector design 110 is configured to reflect, preferablydominantly specularly, the light originally emitted by at least onelight source 104 and incident upon the reflector design 110.

One or more portions of the reflector design 110, or the whole design100, may be located on a side of the plastic layer equal (seereflector/reflector portion 110 a for illustration), opposite (seereflector/reflector portion 110 b for illustration), and/or transverse(see especially reflector/reflector portion 110 c for illustration) to aside facing the first side 102 f of the substrate film 102 hosting thelight source 104.

In preferred embodiments, the reflector design 110 or at least a portionthereof is typically configured to reflect the incident light that haspreviously propagated typically inside the (transmissive) layer 108 toat least roughly towards, or back towards, the layer 108 to prevente.g., undesired light outcoupling from the structure 100 or lightleakage, for instance. In some embodiments, the reflector design 110 maycomprise at least a portion that is, in turn, configured to direct theincident light to alternative direction such as outside the layer 108 orthe whole structure 100.

Further, the reflector design 110 may be configured on or in the layer108 to reflect and steer light emitted by the light source 104 andincident on the reflector design 110 to propagate towards an outcouplingarea 112, 112 a, 112 b, 112 c. In some embodiments to be discussed alsohereinafter, the reflector design 110 may be configured to direct theincident light more towards a surface normal of the layer 108 foroutcoupling the light at least from the layer 108 or the overallstructure.

Indeed, with reference to e.g., sketches in FIGS. 2 and 3 , for example,the reflector design 110 may be configured at least in connection withlight incoupling from the light source 104.

The reflector design 110 or at least portion thereof may be located (110a), 110 b, 110 c on a direct optical emission path from the light source104. Further, the reflector design 110 may be located or comprise aportion 110 b that is located upon and/or opposite to the light source104 (e.g., on the opposite side 108 a of the layer 108 with respect tothe light source 104), aside from and/or under the light source 104 sothat the design 110 receives and reflects and at least part of the lightemitted by the light source 104.

As illustrated, by way of example only, in FIG. 3 at 300, the reflectordesign or a portion thereof 110 b may be configured so as to reflectlight incoupled into the layer 108 from the light source 104 andincident on the reflector design 110 to align more with a lateral planeof the layer 108 substantially transverse to a surface normal of thelayer 108.

Generally, a portion of the reflector design 110, 110 a, 110 b, 110 cmay be located at least partially embedded in the layer 108, and/on thesurface 108 a, 108 b of it.

And as well illustrated, by way of example, in FIG. 2 at 200, the lightsource 104 may be located between at least a portion of the reflectordesign 110 c that is preferably aligned substantially perpendicular tothe light outcoupling area and the light outcoupling area 112. The lightsource 104 may be then aligned in terms of its primary emissiondirection to point at least partially towards the reflector design 110c. For example, the light source, e.g., side-emitting LED or othersource, may be aligned so as to point e.g., about 180 deg away from thedirection of the outcoupling area, 112, 112 a, 112 b, 112 c (shortestpath).

Accordingly, the distance between the light source 104, or light sources104 in a typical scenario of several light sources utilized, andassociated outcoupling area(s) 112, 112 a, 112 b, 112 c may be keptshort and reduced from more conventional solutions as the respectiveoptical distance defined by a path the light emitted by the lightsource(s) 104 actually take prior to outcoupling 112 is increased byroughly two times the distance D illustrated in the figure, i.e. thedistance between the reflector design 110 c and each concerned lightsource 104. This turns into smaller applicable multilayer structuresand/or larger outcoupling area(s) 112, 112 a, 112 b, 112 c obtainablewith decent light mixing characteristics, depending on the preferenceset for the application as being understood by a person skilled in theart.

The reflectance of the reflector design 110 is preferably at leastlocally about 75%, more preferably at least about 90%, and mostpreferably at least about 95% at selected, optionally essentially allvisible, wavelengths of light such at least part of the wavelengthsemitted by the source(s) 104.

To achieve e.g., sufficient reflectivity, the reflector design 110 orsome other optically functional element included in the structure atleast locally preferably comprises at least one element selected fromthe group consisting of:

-   -   electrically conductive material, such aluminum, silver, gold,        zinc, copper, or beryllium;    -   metal, optionally metal particles, further optionally provided        upon or within the substrate film or further film or a further        film or layer included in the structure;    -   a plurality of stacked, superimposed material layers of at least        two mutually different refractive indexes, optionally defining a        Bragg mirror;    -   thin-film coating, optionally PVD (physical vapor deposition)        coating; and    -   (reflective) preferably printable ink or paint.

Accordingly, through utilization of conductive materials such as metalsin one or more layers of the reflector design 110, a so-called skindepth of the reflector design 110 and the whole underlying structure canbe kept small and thereby, reflection efficiency high. Conductivematerials and metals may be provided e.g. in a film, paint, ink, orextrusion (e.g., metal particles in a host material such as plastics)process. In principle, any practical metallization procedure may beapplied to provide the metal(s).

Alternatively or additionally, a plurality of stacked layers(potentially even tens or hundreds of layers) may be applied toestablish a jointly effective, preferably integral, reflectivestructure, such as a Bragg mirror. In such structures, layers ofdifferent refractive indexes may alternate in a sequence. For example,two materials of different refractive index may be configured toalternate in a multilayer reflector stack constituting at least portionof the reflector design 110. At each interface between the two materiallayers a Fresnel reflection is advantageously created. When the opticalpath length difference between subsequent layers is half of thewavelength (i.e., each layer is quarter wavelength thick), thereflections interfere constructively (zero/360 deg phase shift betweenreflections). For example, plastic polymer materials may be utilized inthe multilayer reflector stack, such as e.g. PMMA and PC or PS. Thestacked integral multilayer element may in some embodiments also includesubstrate film 102 and/or other film(s) or generally layer(s) orfeature(s), such as item(s) 114, 116, the subject being discussedfurther hereinbelow in more detail.

The stack included in the reflector design 110 may be realized as anoptionally ready-made multilayer film. Alternatively, several,optionally stacked, material layers of the reflector design 110 may beproduced by a selected coating technique (e.g., PVD or electroplating onplastics) on a substrate, such as the substrate film 102. Alternativelyor additionally, e.g. (multiple) co-extrusion process may be applied.

Item 114 briefly refers to at least one further, optionally additivelyproduced by printing, for example, material layer, optionally stackedand further optionally in contact with the reflector design 110. The atleast one further material layer 114 preferably has a lower refractiveindex than the layer 108. For example, the layer 114 could comprise PMMAwhen the layer 108 is of PC.

The at least one further material layer 114 and the layer 108 may beoptically connected, optionally also physically adjacent, so as toredirect at least part of the light emitted by the light sourcepropagated within the plastic layer 108 and incident upon the at leastone further material layer 114 back towards and into the plastic layerby total internal reflection (TIR) at their interface. In general, ande.g., in cases wherein the reflector design 110 is stacked with andlocated e.g., behind the interface of layers 108, 114 on the opticalpath, it 110 may effectively cooperate with the interface and reflecte.g. the remaining light that has passed through the interface e.g. atangles lower than a related critical angle and is thus incident on thereflector design 110 behind.

At least a layer or other portion of the reflector design 110, a layerof the at least one further material layer 114, and the layer 108 maythus be at least locally superimposed in terms of their materials sothat the material of the layer of the at least one further materiallayer 114 is stacked between the materials of the reflector design 110and the layer 108.

Generally, at least portion of the reflector design 110, 110 a, 110 b,110 c and the at least one further material layer 114 may mutuallyreside on the same, opposite, or both/several sides 108 a, 108 b of thelayer 108.

The at least one further material layer 114 may optionally comprise orconsist of e.g., optically clear adhesive (OCA) or primer.

Generally, utilizing e.g., patterned selective low(er) refractive indexmaterials e.g., in layer 114 or elsewhere, light propagation in thestructure may effectively, both technically and cost-wise, controlled.For instance, with large structures having one or more light sources104, selectively producing light guiding and light guiding enhancingsuch as reflective (border) structures may turn out advantageous. Lightguiding structures such as item(s) 108, 110, 114, 116 can be constructede.g., sector-wise having different optical properties and e.g. lengthsor generally dimensions.

In some embodiments, an integrated multilayer construction, such as amultilayer film 102 a, may be included in the structure 100 as aprefabricated or in situ fabricated element.

The multilayer film 102 a may include a plurality of, e.g. two, stackedand attached, optionally co-extruded, layers one of which may be orestablish the substrate film 102 or similar layer for hosting the lightsource 104 as well as the circuit design 106 and potential additionalelectronics or other elements, while at least one other layer may be atleast one layer of item 114 and/or of the reflector design 110, 110 a(which may itself be a multilayer material stack as discussedhereinbefore), for example, among other options.

In some embodiments, an intermediate layer 116 may be provided in thestructure, e.g. between the layer 108 and a layer of the at least onefurther material layer 114 (if present), and/or between the layer 108and reflector design 110, 110 b, on the first side 108 a of the layer108.

The intermediate layer 116, embodied e.g., as a film, may also act as asubstrate (surface) for various elements such as electronic componentsincl. light sources. The intermediate layer 116 may comprise opticallytransmissive material optionally same as that of the layer 108 or has atleast a similar refractive index therewith. Previous considerationsprovided herein regarding the substrate film 102, may also be generallyapplied to the intermediate layer 116 as being appreciated by a personskilled in the art.

The intermediate layer 116 and the layer of said at least one furthermaterial layer 114 and/or at least one layer of the reflector design110, 110 b may further be constituents of a multilayer construction suchas multilayer film 116 a, further optionally being a co-extrudedmultilayer film.

Items 120, 122 refers to one or more elements such as material layersoptionally at or at least close (preferably within one or two materiallayers) to any of the exterior surfaces of the structure on either sideor both sides 108 a, 108 b of the layer 108. They 120, 122 may includefilms, coatings, prints, plastic materials, natural materials (leather,etc. as listed e.g., in connection with applicable substrate film/filmmaterials hereinbefore). The item(s) 120, 122 may host other features(e.g., electronic components) or layers, and be thus also consideredsubstrate(s) depending on the embodiment. Preferably the items 120, 122are at least translucent in places, comprise optionally filled (with atleast translucent material) (through-)holes or cover only limitedarea(s) to enable light outcoupling from the structure. Differentlamination, printing, coating, molding, or extrusion methods may beutilized for providing any of the items 120, 122, for example.

Item 118 refers to one or more outcoupling elements the structure maycomprise e.g., either as originally separate or integral, if not evenmonolithic, with any of the remaining elements such as the reflectordesign 110 or various (other) material layers.

For instance, the reflector design 110, such as a layer or other portionthereof, or a further element or specifically layer of the structurehaving light emitted by source 104 incident thereon may host, be ordefine a locally treated, preferably mechanically, chemically orelectrically treated, optionally deformed, such as stretched, portion,such as a material stack portion (locally two or more, optionally alllayers of the stack deformed) or a material layer portion, withrespectively altered reflective properties for light redirection andoutcoupling (altered implying reduced reflection, for instance),optionally through the layer 108 or more directly without (anymore)going through the layer 108. As a hands-on example, such outcouplingelement 118 could be provided to the reflector design 110 (to one ormore associated material layers) on one side of the layer 108, e.g.,side 108 b so that at least portion of the light incident on the element118 is then outcoupled either via the surface 108 a of the layer 108after having passed through the layer 108 or via the bottom (as orientedin the figure) surface of the structure potentially without entering thelayer 108 anymore.

As alluded to hereinbefore, instead of or in addition to the reflectordesign 110, other element of the structure such as the layer 108 maylocally host or define e.g. a surface feature or a surface patternconstituting at least portion of an outcoupling element 118, optionallycomprising a roughened or otherwise deformed area, for outcoupling lightthat is internally incident thereon.

Any of the elements 118 may be scattering/diffusing or collimating, forexample.

In a cross-sectional sketch of FIG. 5 , at 500, a plurality ofoutcoupling elements 118 have been illustrated, comprising a number ofpreferably printed, optionally scattering, elements of spatiallymutually varying density of incidence and/or dimensions, preferablyincluding at least thickness, upon the layer 108.

Accordingly, in the illustrated and other use scenarios and embodiments,the density of incidence, thickness and/or one or more other dimensionsof the outcoupling elements 118 may be configured to increase withdistance from the light source(s) 104 to respectively enhanceoutcoupling performance with distance (e.g., at least relatively, incontrast to outcoupling performance of a closer element 118), one ormore of said number of outcoupling elements optionally comprisingfluorescent, phosphorescent, thermochromic or photochromic material.

For the sake of completeness and to facilitate understanding differentconfigurations the embodiments of the present invention may in eachapplication adopt, FIG. 13 illustrates, at 1300, an alternativearrangement of material layers included in the structure. In particular,at least portions of the reflector design 110 such as one or morelayer(s) thereof if not the design as a whole, may at least locallyneighbor the layer 108 and/or be stacked between the layer 108 and e.g.,film 102, whereas in the sketch of e.g., FIG. 1 the reflector design 110was illustrated behind the film 102 from the perspective of the layer108, i.e. closer to or at the exterior or outer surface of thestructure.

Yet, in some embodiments at least a portion of the reflector design 110may be positioned adjacent the substrate film 102 so as to enable lightto incouple from the light source 104 into the substrate film 102 andsubsequently propagate within the substrate film 102 by reflection(mirror, TIR, etc. depending on the neighbouring elements orspecifically, layers) until incident on an outcoupling area 112 orelement 118 allowing the light then to proceed outside the substratefilm 102 and optionally through the plastic layer 108 either intofurther layer(s) and/or the environment. The concerned outcoupling area112 or element 118 may in also this scenario comprise or consist of adeformed substrate or generally material portion, a coating, or aprinted portion, for instance.

FIG. 4 illustrates, at 400, via a cross-sectional sketch, an embodimentwherein a number of holes 410 have been configured in the reflectordesign 110 to enable or facilitate light outcoupling through thereflector design 110 and optionally out from the overall structure,still naturally depending on the optical transmission characteristics ofsubsequent, upper (in the figure) layer(s) and element(s) in the opticalpath. Accordingly, the figure also depicts potential configuration of anumber of further layers in the optical path for light outcoupling fromthe structure, wherein one or more of the further layers or elements412, 414, 416 may also be provided, at least in places, with holes,which may in turn be configured as stacked or laterally aligned with theholes of other layers such as the holes 410 in the reflector design 110.As shown in the FIG. for illustrative purposes, on the left, a hole 410goes through all the layers upon the layer 108, whereas the holes 410 onthe right are only present in items 110, 412.

One or more holes 410 in any of the items 110, 412, 414, 416 may be leftfree from material (may thus accommodate e.g., air during themanufacturing process of the multilayer structure) or be filled withsuitable material such as optically at least translucent if nottransparent material, optionally e.g. glass or plastics such asthermoplastic material. The fill material may be optically diffusive,for instance.

The configuration of holes 410 in the reflector design 110 andoptionally further layers 412, 414, 416 may be made regular ornon-regular in terms of selected characteristics such as density ofincidence, shape or the size (e.g., diameter). The density of incidenceand/or size of holes preferably increases with distance from the lightsource 104 in cases, where the distance from the source-induced lossesare to be compensated in the outcoupled light in favour of more uniformillumination, for instance. At 420, a top/plane view of the reflectordesign 110 and potential further layer(s) thereon is depicted tovisualize how the configuration of associated holes 410 may be adaptedspatially e.g., responsive to the distance from the source(s) 104.

Any of the holes 410 may have been created in any of the items 110, 412,414, 416 through perforation or otherwise subtractively includingremoval of material from the items in favour of the holes 410 created.Also, an additive process may be applied to produce a layer with anumber of holes, with reference to molding and printing technologies,for example. The holes may have e.g., 50-200 um diameter and/or roundshape, but also other sizes and shapes are technically feasible.

The holes 410 may be through-holes but also the use of one or morenon-through holes is feasible if the remaining material at the locationof a hole implements a translucent, transmissive layer, for instance,which may anyway require sticking to somewhat low material thicknesslocally as being easily comprehended by a person skilled in the art.

A hole or multiple holes 410 could also be generally considered in manyuse scenarios as an embodiment, or at least part of an embodiment, ofoutcoupling elements 118 further discussed e.g., in connection with thedescription of FIG. 14 and hereinelsewhere. Thus, instead of in additionto holes, other features breaking/deforming or otherwise locallyaltering a target element such as a target layer could be utilized,still optionally following the principles, mutatis mutandis, set forthabove regarding the holes.

Item 412 refers to a preferably opaque masking element or layer, whichmay be, for instance, printed (e.g., white print), co-prepared such asco-extruded, coated, otherwise prepared or laminated (e.g., a filmlaminated optionally using pressure, adhesive, etc.) on other element orlayer, such as the reflector design 110.

Item 414 refers to a diffuser element or diffuser layer, which may be,for instance, printed, co-prepared such as co-extruded, coated,otherwise prepared or laminated (e.g., a film laminated optionally usingpressure, adhesive, etc.) on other element or layer, such as thereflector design 110.

Item 416 refers to at least one, at least locally translucent, if nottransparent, element or layer, which may be, for instance, printed,co-prepared such as co-extruded, coated, otherwise prepared or laminated(e.g., a film, which may be optionally laminated using pressure,adhesive, etc.) on other element or layer, such as the reflector design110.

The item 416 may have protective function and/or indicative function (itmay contain graphical indicators such as symbols optionally produced byprinting) in addition to aesthetic or look-and-feel type role.

As being appreciated by a person skilled in the art, any of theafore-discussed items 412, 414, 416 may be provided in the structure asa ready-made element, prepared in situ thereon, or installed togetherwith one or more of the other items 412, 414, 416 added. Items 412, 414,and/or 416 may further establish at least portion of item 120 or 122previously discussed.

FIG. 6 illustrates, at 600, an embodiment incorporating an embeddedcircuit board 602 for hosting the light source 104 and potentiallyfurther electronics, as well as a reflector design 110 including aparabolic reflector surface 610. In some embodiments, the circuit board602 could be left out and the light source 104 provided upon thesubstrate film 102 directly or via some other intermediate entity suchas material layer.

By providing at least the light source 104 on a circuit board 602, alighting module containing at least these two may be convenientlyprovided upon the substrate film 102, attached using e.g., conductiveand/or non-conductive adhesive(s), and preferably electrically connectedto the circuit design 106 thereon using e.g., conductive ink oradhesive. The circuitry on the board 602 may include a local circuitdesign or sub-design with e.g. conductive traces or pads for connectingcomponents such as light source(s) 104 with other components orelements, e.g. control or communication circuit, in a desired fashion atleast locally on the board 602.

By utilizing the board 602, heat management of the remaining structuremay be facilitated and the wattage of one or more light sources 104and/or of some other high-power component included may be about 1 W ormore, even significantly more, for example. Optionally, there may be aplurality of light sources of mutually similar or differentcharacteristics (wavelength/color, power, emission direction, beamwidth, technology, etc.) on the board 602.

The circuit board 602 may comprise at least one element selected fromthe group consisting of: a flexible film or sheet, a rigid sheet,rectangular sheet or film, rounded or essentially circular sheet orfilm, FR4 based circuit board, metal core circuit board, plasticsubstrate, molded such as injection molded plastic substrate, metalsubstrate such as sheet metal substrate optionally having anelectrically insulated layer at least selectively provided thereon, anda ceramic circuit board.

In various embodiments, the circuit board 602 or e.g., the substratefilm 102 or some other substrate layer in the structure may host variouselectrical and/or other elements, such as series resistor, thermistor,white solder mask, trace, antenna, sensor, electrode such as acapacitive sensing electrode, contact pad, integrated circuit,controller, processor, memory, transceiver, driver circuit, optionallyoptically clear glob top or other conformal coating, and via such aselectrical, fluidic and/or thermal via.

Generally, the circuit board 602 may be planar and preferably round ifnot essentially circular or elliptical by its general shape. Thedimensions, shapes and thickness of the circuit may vary depending onthe use case. Therefore, e.g., rectangular shape is possible as well.Thickness may be a fraction or portion of a millimeter (e.g., betweenabout 0.2 and about 0.6 mm), a millimeter, few millimeters, or more, forexample. Yet, the diameter may be few millimeters, about one centimetre,or few centimeters among other options. Castellations may be provided atthe edges for convenient edge connections.

E.g., in case the circuit board 602 is not itself made from translucentor transparent material, the circuit board 602 may at least be providedwith a number of holes 603 to enable the light emitted by the source(s)104 and reflected from the parabolic reflector 610 to conveniently passthrough towards the environment and e.g., potential user 113 thereinwithout undesired issues such as shadows in the obtained distribution oflight. Naturally, the concept of utilizing a preferably hole-providedcircuit board for accommodating the light source 104 and/or otherelectronics or element(s) is feasible also in embodiments not comprisingthe parabolic reflector 610. The holes 603 may be filled with opticallytransmissive, at least translucent if not transparent material, e.g. bythe material of the layer 108 upon producing it by molding, for example,which may optionally further secure the board 602. In the shownscenario, naturally the substrate film 102 and potential layer(s) orother element(s) thereon shall preferably also be at least translucentat least in places to enable light transmission therethrough.

In any case, the reflector design 110 may at least locally define acollimating reflector surface 610, optionally essentially a parabolicreflector, preferably on a side 108 a of the layer 108 opposite to aside 108 b facing the first side of the substrate film 102 hosting thelight source(s) 104. The surface 610 or the reflector design 110 ingeneral may be obtained, for example, by a selected coating methodapplied on a host surface as discussed hereinelsewhere. The parabolichost protrusion or “bumb” surface shape on surface 108 a in the layer108 may in turn be obtained during molding and/or printing of the layer108 by utilizing a suitable mold shape or afterwards by a selectedsubtractive or additive processing, for example. The opposite surface108 b may be kept smooth, which may turn out beneficial in applicationsrequiring a flat film 102 surface or e.g., overall exterior surfacefacing the (use) environment of the structure, for example. Theassociated motives may vary but include e.g., surface treatments,functionalities (e.g., touch sensing) or aesthetics benefiting from orrequiring a substantially flat target.

FIG. 7 illustrates, at 700, another potential embodiment involving aparabolic reflector surface and shape. Light source(s) 104 have beenthis time off-centered from the optical axis or axis of symmetry of thereflector shape and thus located aside from a related light aperture,and again, e.g. undesired shadowing may be avoided or at least reducedon the illuminated surface upon film 102. Optionally, circuit board(s)602 could also be utilized in this scenario (not illustrated).

FIG. 8 illustrates, at 800, an embodiment of an illumination ensembleincluding a plurality of mutually different multilayer structuresgenerally discussed herein. Two or more of such structures 801 a, 801 bmay be prepared, stacked and preferably attached (adhesive, mechanicalfixing elements or other methods of bonding may be used here) togetherto establish also functional ensemble. Alternatively, the ensemble 800could be constructed otherwise, e.g., layer-wise. The ensemble 800 maybe configured to outcouple light from each of the structures 801 a, 801b via their individual, optionally at least partially non-overlapping,outcoupling areas 112 a, 112 b on one or more surfaces of the ensembleand/or illuminated outcoupling elements 812 a, 812 b within and/or onthe surface of the ensemble. The outcoupling areas 112 a, 112 b may beassociated with characterizing visuals such as e.g. printed ormask-based graphics provided on any of the illuminated surface layer(s)120, whereupon independently controlling the light output from thestructures 801 a, 801 b and optionally further from the included lightsources 104 in case one or more of the structures 801 a, 801 b comprisesseveral independently controllable sources 104, may be utilized toselectively illuminate the visuals and generally render them visible forexternal perception. Accordingly, functionally complexilluminated/illumination structures may be constructed from simpler,combinable constituent assemblies, which are mutually different orsimilar in terms of structure, dimensions, and/or included features orrelated functionalities.

FIG. 9 illustrates, at 900 (cross-sectional view, see A-A cut line) and901 (top/planar extract view) an embodiment wherein a lighting orillumination module is included in the structure, comprising at leastone light source 104 (in the shown example, six) on a circuit board 602(on the substrate film 102) further potentially hosting additionalelectronics or optics.

The circuit board 602 may optionally further host optical element(s)such as a lightguide 908 comprising optically transmissive (transparentor at least translucent) material such as thermoplastic material(s)discussed hereinelsewhere, covering one or more light sources 104. Yet,a wall structure 902 preferably at least in places comprising opticallytransmissive and optionally clear material has been advantageouslyarranged at the periphery of the circuit board 602. Further, there maybe an air gap or fill 909 (again, preferably comprising transparent orat least transparent material) preferably between the wall structure 902and the lightguide 908. The circuit board 602 may further comprise anumber of optionally filled (translucent/transparent fill) holes 603 forenabling light transmission therethrough as deliberated hereinbefore.

FIG. 11 illustrates, at 1100, an embodiment with multiple light sources104 and other circuitry 105 such as related control circuitry includedin the structure.

The control circuitry 105, such as driver circuitry, controller chipsuch as a microcontroller, microprocessor, (other) integrated circuit orthe like, may optionally comprise elements at least partially integralwith any of the light sources 104 instead of or in addition to beingseparate from while still electrically connected, e.g., via circuitdesign 106, with them 104. Preferably, the circuitry 105 is configuredto dynamically and/or independently adjust e.g., the intensity and/orother characteristics (e.g. color distribution when applicable) of lightemission of each of at least two of the light sources 104. However, alsojoint control may be additionally or alternatively enabled for two ormore light sources 104. Yet, the circuitry 105 may at least functionallyconnected to external circuitry via wiring and connector(s), forinstance, power data and/or power transfer.

For a light source 104, such as a LED, e.g. PWM (pulse width modulation)or current control may be utilized for the purpose. Control circuitry105 can be included in the structure also in cases where only singlelight source 104 is present.

FIG. 12 illustrates (at 1200 via a cross-sectional top view, at 1202skeletonized view in A-A direction, at 1204 cross-sectional view alongB-B) an embodiment including a bend in the layer 108.

At least the layer 108 indeed defines a bend, optionally having a bendangle of about degrees or more, potentially even about 30 or 45 degrees,or more, and at least a portion of the reflector design 110 is locatedessentially at an outer and/or inner perimeter thereof on the layer 108.Reflective portions 110 a, 110 b, 110 c, 110 d have been thusillustrated in the figure accordingly.

By utilizing the reflector design 110, bends and other similar, morecomplicated shapes may be carried out in the layer 108 and generalstructure without essentially losing optical efficiency. In addition tothe reflector design 110, TIR type interfaces and related enablingelements or layers (e.g., layer 114) may be included in the structure tomaximize lightguiding efficiency as more thoroughly discussedhereinelsewhere.

FIG. 14 further illustrates, at 1400, different options andconfigurations for light outcoupling in connection with variousembodiments of the present invention, some of which have also beencontemplated in connection with the description of other FIGS. appendedherewith.

Accordingly, a number of outcoupling elements 118 such as particularshapes and/or material layers for controlling or enhancing outcouplingmay be provided e.g., in the optical path from the light source 104towards the exterior of the structure and e.g., as embedded, at thesurface of, or subsequent (optical path-wise) to the layer 108.

Item 1412 refers to a type of an outcoupling element 118 comprising amaterial layer and/or other outcoupling feature being part of thereflector design 110 or adjacent it in the structure, for example, butcomprising features for enhancing light outcoupling.

The outcoupling elements 118, incl. 1412, may therefore comprise:

-   -   a locally dented or protruding surface such as the surface of        the layer 108 optionally defining one or more e.g., prismatic        dent or protrusion shapes 1418;    -   an element or specifically, a layer 1412 a of optically at least        translucent if not transparent material with a refractive index        lower than of optically subsequent, adjacent material such as        air, and/or a perforated, holey or otherwise locally thinned or        through-cut layer of opaque material;    -   an element or specifically, a layer 1412 b with holes (no fill,        or translucent/transparent fill) in the carrier material (may be        opaque);    -   an element or specifically, a layer 1412 c of alternating higher        1414 and lower 1416 refractive index materials; and    -   adhesive or adhesion promoting primer, preferably substantially        being of optically transparent or at least translucent type (may        act as cladding material).

FIG. 15 illustrates, at 1500, an embodiment of the multilayer structure(or ensemble of structures), further incorporating supplementaryfunctionality such as touch or gesture sensing (optionally contactless)in addition to illumination. The supplementary functionality may beprovided, e.g., as an integral construction or layer-wise, by additionallayers and other elements arranged on the multilayer structurecontaining the light source(s) 104 and further optical features.

For instance, a diffuser element 414 such as a film or coating may beprovided.

Preferably at least translucent or substantially transparent,essentially planar electrode 418 may be provided, optionally printed onthe diffuser 414 or other adjacent element or layer, e.g. 416 b. Theelectrode 418 may be electrically or electromagnetically connected toother circuitry 105 such as driving or sensing circuitry also positionedin the structure and/or external thereto. Electrical wiring or wirelessconnectivity may be applied for the purpose.

As mentioned hereinbefore, item 416 refers to at least one, at leastlocally translucent, if not transparent, element or layer, which may be,for instance, printed, co-prepared such as co-extruded, coated,otherwise prepared or laminated (e.g., a film laminated optionally usingpressure, adhesive, etc.) on other element or layer, such as thereflector design 110. For example, item 416 may thereby comprise e.g.,printed graphics 416 a, optionally laterally adjacent the electrode 418and/or a protective exterior surface element 416 b of optionallytranslucent, non-transparent type, which still preferably enablesexternally perceivable backlighting (i.e., not fully opaques). Item 416may comprise (perforated, thin(ned) or otherwise treated, configured, orselected to enable at least local translucency/transparency) plastics,metal or wood, leather, or other biomaterials, inks, fabric, etc.

FIG. 10 shows, at 1000, a flow diagram of an embodiment of a method formanufacturing an integrated optically functional multilayer structure inaccordance with the present invention. As applicable manufacturingprocesses and related characteristics regarding possible constituentelements and materials of various embodiments of the structure havealready been discussed also hereinbefore, these discussions are notunnecessarily repeated here in favour of clarity of the overall, alreadylengthy method description. However, a person skilled in the art willappreciate the fact that they can revert to the previous paragraphs forfinding valuable details also with respect to applicable manufacturingmethods and considerations, while in terms of structural or functionaldetails potentially included in the multilayer structure, the sameapplies also in reverse direction.

At the beginning of the method for manufacturing the multilayerstructure, a start-up phase 1002 may be executed. During the start-up,the necessary preparatory tasks such as material, component and toolsselection, acquisition, calibration and other configuration tasks maytake place. Specific care must be taken that the individual elements andmaterial selections work together and survive the selected manufacturingand installation process, which is naturally preferably checked up-fronton the basis of the manufacturing process specifications and componentdata sheets, or by investigating and testing the produced prototypes,for example. The used equipment such as molding, IMD (in-molddecoration), lamination, bonding, (thermo)forming, electronics assembly,cutting, drilling, perforation, printing and/or measurement such asdesired optical measurements-providing equipment, among others, may bethus ramped up to operational status at this stage.

At 1004, at least one, preferably flexible, substrate film of plasticsor other material for accommodating e.g., light source(s) andpotentially other electronics is obtained. The substrate film mayinitially be substantially planar or e.g., curved. The substrate filmmay at least dominantly be of electrically substantially insulatingmaterial(s). A ready-made element, e.g., a roll or sheet of plasticfilm, may be acquired for use as the substrate material. In someembodiments the substrate film itself may be first produced in-house bymolding using a mold or molding device or other methods from selectedstarting material(s). Optionally, the substrate film may be processedfurther at this stage. It may be, for example, provided with holes,notches, recesses, cuts, etc.

Item 1014 refers generally to the provision of the reflector design. Asbeing understood by a person skilled in the art also based on theprevious contemplations herein, the reflector design or portion(s)thereof may be provided, by installation or in situ manufacturing, atdifferent method phases to the structure depending on, not just theconfiguration of the reflector design itself, but also on other elementsand their configuration in the structure. Yet, as the reflector designor a portion of it may also be provided as ready-integrated with furtherelements such as films or generally material layers, in some embodimentsitem 1014 may be integrated with other items. For example, a combinedelement of e.g., multilayer type for implementing a substrate forelectronics and reflective structure or layer(s) could be obtainedalready at 1004.

The curved arrows thereby indicate that the order of pointed methoditems may be reversed and/or the items integrated or further split,depending on the particular embodiment in question.

The reflector design and related material layer(s) may be generallyprovided by printing, coating, laminating or molding, for instance. Yet,the process may include formation of various features such as holes inthe reflector material and potentially filling them with othermaterials, or provision of outcoupling elements as discussed in moredetail hereinbefore. The reflector design may comprise one or morematerial layers, optionally comprising a stack of material layers and/ora layer of electrically conductive and/or metallic material, forexample. Yet, the reflector design such as layer(s) thereof may includeor be arranged with further elements such as openings (holes). Thereflector design is configured to reflect, optionally dominantlyspecularly, the light emitted by at least one light source included inthe structure to be manufactured and incident upon the reflector design,optionally and in most common use cases, towards a plastic layer 108provided at item 1012.

At least portion of the reflector design, such as one or more layers,may be provided on the substrate film(s) prior to the provision ofplastic layer, see item 1014A. Alternatively or additionally, at leastportion of the reflector design could be provided subsequent to or uponarranging the plastic layer on the substrate film or between thesubstrate film and another film, potentially being a further substratefilm to reside on the other side of the intermediate plastic layer 108established, see item 1014B.

Yet, the shown two one-directional dotted arrows further indicateadditional or alternative process-wise options for the provision ofreflection design 1014, essentially between item 1008 and 1010, and/orbetween item 1010 and 1012, or in connection with any of theaforementioned three items.

At 1006, a number of electrically and optionally thermally conductiveelements defining e.g., various conductor lines (traces), sensingelements such as electrodes, and/or contact areas such as pads toconstruct a circuit design are provided on one or more of the substratefilm(s), preferably by one or more additive techniques of e.g., printedelectronics technology or 3D printing. Accordingly, the circuit designmay comprise several circuits or circuit sub-designs on different layersof the overall construction, optionally being connected via conductivewiring e.g., through intermediate layer(s) or via the edge of thestructure. For example, screen, inkjet, flexographic, gravure or offsetlithographic printing may be applied by a suitable printing device ordevices for producing at least portion of the circuit design. In somecases, also subtractive or semi-additive processes may be utilized.Further actions cultivating the substrate film(s) involving e.g.,printing or generally provision of graphics, visual indicators, opticalelements such as masks or outcoupling elements, holes/fills, etc.thereon or thereat may take place here if not already executed e.g., at1004.

In various embodiments the electrically and optionally thermallyconductive elements (traces, pads, connection elements, electrodes,etc.) may include at least one material selected from the groupconsisting of: conductive ink, conductive nanoparticle ink, copper,steel, iron, tin, aluminium, silver, gold, platinum, conductiveadhesive, carbon fibre, graphene, alloy, silver alloy, zinc, brass,titanium, solder, and any component thereof. The used conductivematerials may be optically opaque, translucent and/or transparent atdesired wavelengths, such as at least portion of visible light, so as tomask or let the radiation such as visible light to be reflectedtherefrom, absorbed therein or get through, for instance. This aspecthas also been discussed elsewhere herein. As practical examples offeasible conductive material, e.g. Dupont™ ME602 or ME603 conductive inkmay be utilized.

At 1008 further circuitry such as one or more typically ready-madecomponents including electronic components such as various SMDs isattached to the contact areas on the film(s) e.g. by solder and/oradhesives. For example, light source(s) (e.g., LEDs) of selectedtechnology and packaging as contemplated hereinbefore may be providedhere as well as e.g., different elements of control and/or drivingelectronics, communication, sensing, connecting (e.g. connectors),hosting (circuit board(s), carrier(s), etc.) and/or power provision(e.g. battery) depending on the embodiment.

A suitable pick-and-place or other mounting device may be utilized forthe purpose, for instance. Alternatively, or additionally, printedelectronics technology may be applied to actually manufacture at leastpart of the components, such as OLEDs (organic LED), directly onto thefilm(s) in situ. Accordingly, the execution of items 1006, 1008 toprovide the multilayer structure with desired circuitry may temporallyoverlap as being understood by a skilled person. Yet, the componentsprepared or installed herein may also include various optical elementssuch as lenses, reflectors, diffusers, masks, filters, etc.

Non-conductive and/or conductive adhesive may be utilized for securingthe components. In some embodiments, mechanical securing is implementedor at least enhanced by non-conductive adhesive material whereas solderor other electrically highly conductive (but to lesser extent, adhesivetype of) material is used for electrical connection.

Selected elements may be subjected to further processing such asencapsulation (see e.g., overcoat related comments providedhereinearlier).

Item 1009 specifically refers to preparation and attachment of one ormore, at least partially pre-prepared, modules, such as theafore-discussed lighting module incorporating at least one light source104 and e.g., circuit board 602, or other ‘sub-assemblies’, which mayincorporate an initially separate, secondary substrate such as a circuitboard provided with a local circuit design and electronics such as anumber of light source(s), IC(s) and/or various other elements orcomponents, such as optical or structural ones (e.g. wall structure,diffuser, lens, carrier elements, etc.), as being contemplated alsohereinearlier in more detail.

At least part of the electronics and/or other elements of the finalmultilayer structure may be thus conveniently provided to the substratefilm(s) via fully or partially pre-manufactured module(s) orsub-assembly/assemblies. Optionally, a concerned module or sub-assemblymay be at least partially overmolded or generally covered by protectivematerial such as plastic layer prior to attachment to the mainsubstrate.

For example, adhesive, pressure and/or heat may be used for mechanicalbonding of the module or sub-assembly with the primary (host) substrate.Solder, wiring, and conductive ink are examples of applicable optionsfor providing the electrical and/or thermal connections between theelements of the module or sub-assembly and with the remaining electricaland/or thermal elements on the main substrate. Item 1205 could also beexecuted e.g., upon item 1204 or 1208. The shown position is thereforeprimarily exemplary only.

Still, the circuitry generally included in the multilayer structure,e.g. on a substrate film, may comprise at least one component or elementselected from the group consisting of: electronic component,electromechanical component, electro-optical component,radiation-emitting component, light-emitting component, LED(light-emitting diode), OLED (organic LED), side-shooting LED or otherlight source, top-shooting LED or other light source, bottom-shootingLED or other light source, radiation detecting component,light-detecting or light-sensitive component, photodiode,phototransistor, photovoltaic device, sensor, micromechanical component,switch, touch switch, touch panel, proximity switch, touch sensor,atmospheric sensor, temperature sensor, pressure sensor, moisturesensor, gas sensor, proximity sensor, capacitive switch, capacitivesensor, projected capacitive sensor or switch, single-electrodecapacitive switch or sensor, capacitive button, multi-electrodecapacitive switch or sensor, self-capacitance sensor, mutual capacitivesensor, inductive sensor, sensor electrode, micromechanical component,UI element, user input element, vibration element, sound producingelement, communication element, transmitter, receiver, transceiver,antenna, infrared (IR) receiver or transmitter, wireless communicationelement, wireless tag, radio tag, tag reader, data processing element,microprocessor, microcontroller, digital signal processor, signalprocessor, programmable logic chip, ASIC (application-specificintegrated circuit), data storage element, and electronic sub-assembly.

In some embodiments, prior to or upon item 1012, the substrate film(s)optionally already containing electronics such as at least part of thecircuit design and/or the light source or other circuitry, may beoptionally formed 1010 using thermoforming or cold forming, forinstance, to exhibit a desired shape such as at least locally athree-dimensional (essentially non-planar) shape. Applicable formerdevice such as a thermoformer may be utilized for the purpose.Additionally or alternatively, at least some forming could take placeafter molding in case the already-established multilayer stack isdesigned to survive such processing.

At 1012, an optically transmissive plastic layer or generally layer 108is produced at least upon the first side of the substrate film andpreferably the light source(s) thereon, the plastic layer at leastlaterally surrounding or neighbouring (see e.g., FIG. 9 ), optionallyalso at least partially covering (e.g., FIG. 1 ), the light source(s).

Preferably the plastic layer or in some embodiments, multiple layersprovided, preferably comprising thermoplastic or in some embodimentsoptionally thermoset layer(s), are manufactured through molding such asinjection molding, upon the substrate(s). Desired portions may be leftclear or cleared afterwards with mechanical or chemical processing,considering e.g., a cover portion of lighting module or other moduleintended to host replaceable or generally accessible (e.g., inspectableor reprogrammable) components. Such module may then also include a(re)movable cover part for providing access to the internals thereof.

The molded material(s) may be provided using several molding steps orshots, or via a single step, wherein the molded material may evenoptionally flow through a substrate film from one side thereof to theopposing side via a hole prepared therein or by penetrating through thesubstrate material itself (e.g. through a thinned/thinner portion), forexample. The molding material(s) may be, and in many embodimentspreferably are, at least dominantly electrically insulating. Adhesionpromotion material may be utilized on the films neighbouring the moldedplastics.

In practice, at least one substrate film already provided with a numberof features such as circuitry incl. light source(s), module(s), furtheroptical features, etc. may be used as an insert in an injection moldingprocess applying at least one molding machine. In case two films areused, both of them may be inserted in their own mold halves so that theplastic layer is injected at least between them. Alternatively, thesecond film could be attached to an aggregate of the first film andplastic layer afterwards by suitable lamination technique utilizinge.g., adhesive in between.

Some optical elements contemplated hereinbefore such as a lensstructure, optical outcoupling element, or a diffuser may be at leastpartially established during molding from the used (thermoplastic)material and/or any of the film inserts by proper mold shapes, forinstance.

Instead of or in addition to molding, e.g. (3D) printing could beharnessed into producing the plastic layer.

Regarding the resulting overall thickness of the obtained stackedmultilayer structure, the thickness depends e.g., on the used materialsand related minimum material thicknesses providing the necessarystrength in view of the manufacturing and subsequent use. These aspectsare to be considered on case-by-case basis. For example, the overallthickness of the structure could be in the order of magnitude of aboutsome millimeters as discussed hereinelsewhere, but considerably thickeror thinner embodiments are also feasible.

In some embodiments, material(s) other than plastics could be utilizedin the layer 108, with reference to e.g., glass.

Item 1016 refers to a number of potential additional tasks such aspost-processing and installation tasks. Further layers, single-layer ormultilayer films, or generally additional features, may be added intothe multilayer structure by molding, printing, lamination e.g, by heat,adhesive, or pressure, or suitable coating (e.g. deposition) procedure,not forgetting other possible positioning or fixing techniques andsubtractive technologies such as lasering. The layers may be ofprotective, indicative and/or aesthetic value (graphics, colors,figures, text, numeric data, etc.) and contain e.g., textile, leather orrubber materials instead of or in addition to plastics.

Additional elements such as electronics, modules, module internals orparts, and/or optics may be installed and fixed e.g., at the outersurface(s) of the existing structure, such as the exterior surface of anincluded film or a molded layer depending on the embodiment. Forexample, optical features such as a lens structure or a diffuser couldbe constructed or finalized here by processing the thermoplastic layeror any further layer or element thereon by adding material thereon orremoving material therefrom (lasering is one option).

Features potentially present in the multilayer structure indeed includevarious previously discussed features such as diffusers, outcouplingelements, optical masks, holes, graphics, protective and/or aesthetic(and/or tactilely preferred) films or layers, etc. Such features may beprovided at this stage or during any previous method item depending ontheir position and generally configuration in the resulting structure aswell as other features to be included. as being understood by a personskilled in the art.

Some features such as outcoupling elements integrally or monolithicallyformed in a target material as discussed hereinbefore may be provided bymodifying the target material such as the material of the substratefilm, a further film (e.g. 114, 116, 120, or 122) and/or reflectordesign through deformation, optionally involving material stretching.Mechanical pressured introduced by a press, for example, may be used forthe purpose. Mechanical pressure-induced deformations such as materialstretching, breakage and/or undulation taking place inside the structureor on a predefined back side of the structure (not visible e.g., duringuse) do not need to have any effect on the externally perceivablevisuals of the structure.

Furthermore, a feature to be potentially provided in the structure bythe method, optionally as a coextruded film layer or through coating,printing or molding as discussed hereinbefore, is or comprises at leastone further material layer having a lower refractive index than theplastic layer so that said at least one further material layer and saidplastic layer are optically connected, optionally physically adjacent.Accordingly, at least part of the light emitted by at least one lightsource, propagated within the plastic layer and incident upon the atleast one further material layer is reflected (back) into the plasticlayer or is essentially kept there by total internal reflection providedthat a related critical angle is exceeded. The at least one furthermaterial layer may optionally comprise thermoplastic material oroptically clear adhesive material or e.g., primer.

Still further, the method may comprise at least one fabrication orinstallation action selected from the group consisting of:

-   -   laminating two or more layers included in the multilayer        structure together by pressure-sensitive adhesive, optically        clear adhesive, solvent, ink, heat, pressure, or hot melt;    -   additively producing such as printing or 3D-printing at least        one layer such as the plastic layer, a layer of the at least one        reflective layer, a further material layer, a lightguide, a        light outcoupling element, a diffuser, and/or other optically        functional element; and    -   providing a top-emitting light source, optionally LED, on its        side on the substrate film so that its contact pads face a        direction transverse to the surface of the substrate film and        are contacted by conductive adhesive also provided (e.g.,        dispensed) on the substrate film electrically joining the        contact pads with the circuit design, the conductive adhesive        being at least partially surrounded on the substrate film by        structural adhesive provided on the substrate film (this is a        feasible way to turn a top-emitting source operatively into a        side-emitting one).

Even still further, the method may comprise interconnecting a pluralityof modules together to construct the structure, wherein any or eachmodule advantageously comprises

-   -   at least one of        -   one or more light sources;        -   at least a portion of the substrate film; and        -   the circuit design, optionally including a light source            driver circuit and/or a capacitive sensing electrode;            or    -   at least a portion of a layer of the reflector design and/or at        least a portion of the plastic layer.

For example, an electronics and/or illumination module may be produced(comprising e.g. light sources, circuit design and optionally furthercircuitry such as control circuit) as well as a number of simplermodules without e.g., electronics but including e.g., opticallytransmissive and/or reflective material or structure, and then joinedtogether.

Any of the modules may span several layers of the multilayer structure.In addition to being able to construct a multilayer structure at leastpartially from modules of different characteristics, several optionallymutually different or similar multilayer structures may be connected toestablish even larger, functionally more versatile ensembles ascontemplated hereinelsebefore.

If optionally supplementary functionalities such as afore-discussedcapacitive sensing of e.g., touch or touchless gestures upon thestructure are to be implemented, sensing electrodes of the circuitry maybe configured (dimensioned, positioned, etc.) with further elements andlayers, with reference to FIG. 15 and related text, so that theirsensing area or volume defined by e.g., the associated electric orelectromagnetic field is located as desired and thereby covers e.g., thearea upon a top surface of the structure and/or other regions thatshould be made sensitive to touch (and/or touchless gestures in someembodiments) or other sensing target. This type of configuring may beachieved or performed through the utilization of simulation ormeasurement activities, for instance. Necessary features may be builtupon the existing structure in a layer-by-layer fashion or installed asat least partially ready-made stack, for example.

If provided with a connector, the connector of the multilayer structureor ensemble may be connected to a desired external connecting elementsuch as an external connector of an external device, system orstructure, e.g., a host device. For example, these two connectors maytogether form a plug-and-socket type connection and interface. Themultilayer structure or ensemble may also be generally positioned andattached herein to a larger ensemble such as an electronic host device,optionally a personal communications device, computer, householdapparatus, industrial device, or e.g., a vehicle in embodiments whereinthe multilayer structure establishes a part of vehicle exterior orinterior, such as a dashboard or a panel.

At 1018, method execution is ended.

The scope of the present invention is determined by the attached claimstogether with the equivalents thereof. A person skilled in the art willappreciate the fact that the dis-closed embodiments were constructed forillustrative purposes only, and other arrangements applying many of theabove principles could be readily prepared to best suit each potentialuse scenario.

1.-30. (canceled)
 31. An integrated optically functional multilayerstructure, comprising: a flexible, substrate film arranged with acircuit design comprising at least a number of electrical conductors; alight source provided upon a first side of the substrate film tointernally illuminate at least portion of the structure for externalperception; an optically transmissive plastic layer, provided upon thefirst side of the substrate film, said plastic layer at least laterallysurrounding or neighbouring, the light source, the substrate film; and areflector design comprising at least one material layer, said reflectordesign being configured to reflect, the light emitted by the lightsource and incident upon the reflector design.
 32. The structure ofclaim 31, wherein the reflectance of the reflector design is at leastlocally about 75% wavelengths of light.
 33. The structure of claim 31,wherein the reflector design is configured on a direct optical emissionpath from the light source so as to reflect light incoupled into theplastic layer from the light source and incident on the reflector designto align more with a lateral plane of the plastic layer substantiallytransverse to a surface normal of the plastic layer.
 34. The structureof claim 31, wherein the reflector design is configured on or in theplastic layer to reflect and steer light emitted by the light source andincident on the reflector design to propagate towards an outcouplingarea for outcoupling the light at least from the plastic layer or theoverall structure.
 35. The structure of claim 31, wherein the reflectordesign at least locally comprises at least one element selected from thegroup consisting of: electrically conductive material; metal; aplurality of stacked, superimposed material layers of at least twomutually different refractive indexes; thin-film coating; and ink orpaint.
 36. The structure of claim 31, comprising at least one further,material layer, in contact with the reflector design, said at least onefurther material layer having a lower refractive index than the plasticlayer, said at least one further material layer and said plastic layerbeing optically connected, so as to redirect at least part of the lightemitted by the light source, propagated within the plastic layer andincident upon the at least one further material layer back into theplastic layer by total internal reflection, said at least one furthermaterial layer.
 37. The structure of claim 36, wherein a layer of the atleast one further material layer is a layer of the substrate film ofmultilayer, type comprising also a hosting layer for the light source.38. The structure of claim 36, comprising an intermediate layer betweenthe plastic layer and a layer of said at least one further materiallayer, the intermediate layer comprising optically transmissive materialsame as that of the plastic layer or having at least a similarrefractive index therewith, said intermediate layer and the layer ofsaid at least one further material layer, hosting a number of elementssuch as optical elements, a circuit design or one or more electroniccomponents, laminated upon the plastic layer.
 39. The structure of claim31, wherein the plastic layer defines a bend, and at least a portion ofthe reflector design is located essentially at an outer and/or innerperimeter thereof on the plastic layer.
 40. The structure of claim 31,wherein at least a portion of the reflector design comprises a number ofholes, such as a perforation, to enable incident light to propagatethrough for outcoupling, wherein the density of incidence and/or size ofholes increases with distance from the light source.
 41. The structureof claim 31, comprising at least one element, along the optical pathfrom the light source towards the exterior of the structure, selectedfrom the group consisting of: a diffuser; at least translucent orsubstantially transparent, essentially planar electrode; printedgraphics; and protective exterior surface element of non-transparenttype.
 42. The structure of claim 31, wherein the reflector design atleast locally defines a collimating reflector surface, on a side of theplastic layer opposite to a side facing the first side of the substratefilm hosting the light source, wherein the light source is centered oroff-centered in relation to the axis of symmetry of the collimatingreflector surface.
 43. The structure of claim 31, wherein at least aportion of the reflector design is positioned adjacent the substratefilm so as to enable light incoupled from the light source into thesubstrate film to propagate within the substrate film by reflectionuntil incident on an outcoupling area or outcoupling volume allowing thelight outside the substrate film and through the plastic layer.
 44. Thestructure of claim 31, wherein the reflector design contains a locallytreated, mechanically, chemically or electrically treated, portion, suchas a material stack portion or material layer portion, with alteredreflective properties for light redirection and outcoupling.
 45. Thestructure of claim 31, wherein the plastic layer locally defines asurface feature or a surface pattern, for outcoupling light that isinternally incident thereon.
 46. The structure of claim 31, comprising anumber of printed, outcoupling elements of spatially mutually varyingdensity of incidence, thickness and/or other dimensions, upon theplastic layer, the density of incidence, thickness and/or one or moreother dimensions of the outcoupling elements increasing with distancefrom the light source to respectively enhance outcoupling with distance.47. The structure of claim 31, comprising an overcoat at least partiallycovering a light emitting portion of the light source, said overcoatlayer comprising optically transmissive material.
 48. The structure ofclaim 31, comprising a light outcoupling area on the plastic layer,wherein the light source is located between at least a portion of thereflector design aligned substantially perpendicular to the lightoutcoupling area, and the light outcoupling area, and the light sourcehas been aligned in terms of its primary emission direction towards theat least portion of the reflector design.
 49. The structure of claim 31,comprising a circuit board hosting the light source and provided on thesubstrate film, a wall structure of optically transmissive and arrangedat the periphery of the circuit board, and/or air gap or fill betweenthe wall structure and the lightguide.
 50. The structure of claim 31,comprising, in the optical path from the light source towards theexterior of the structure and at the surface of or subsequent to theplastic layer, at least one element selected from the group consistingof: optical print layer, coating or film comprising opaque ortranslucent material relative to the light emitted by the light source,optical mask, layer of optically at least translucent if not transparentmaterial with a refractive index lower than of optically subsequent,adjacent material such as air, layer of alternating higher and lowerrefractive index materials, perforated, holey or otherwise locallythinned or through-cut layer of opaque material, and adhesion promotingprimer.
 51. The structure of claim 31, wherein the light sourcecomprises a semiconductor, a packaged semiconductor, a chip-on-boardsemiconductor, bare chip, electroluminescent or a printed type lightsource.
 52. The structure of claim 31, wherein the opticallytransmissive plastic layer defines a hole therein to accommodate atleast portion of the at least one light source.
 53. The structure ofclaim 31, wherein at least one of the number of electrical conductors ofthe circuit design is partially or essentially positioned on a side ofthe reflector design which faces away from the optically transmissiveplastic layer and at least electrically, connects to the light source.54. The multi-source multi-target illumination ensemble comprising twoor more structures of claim 31, stacked or attached, together,configured to outcouple light from each of said two or more structuresvia their individual, at least partially non-overlapping, outcouplingareas on one or more surfaces of the ensemble and/or illuminatedoutcoupling elements in or on the ensemble.
 55. A method formanufacturing an integrated optically functional multilayer structure,comprising: obtaining a flexible, substrate film, provided with acircuit design comprising at least a number of electrical conductors,additively produced such as printed on the substrate film; arranging atleast one light source upon a first side of the substrate film;providing, an optically transmissive plastic layer upon the first sideof the substrate film, said plastic layer at least laterally surroundingor neighbouring, the light source; wherein a reflector design comprisingat least one material layer, is provided, and configured to reflect, thelight emitted by the at least one light source and incident upon thereflector design.
 56. The method of claim 55, comprising providing, atleast one further material layer having a lower refractive index thanthe plastic layer so that said at least one further material layer andsaid plastic layer are optically connected, so as to redirect at leastpart of the light emitted by the at least one light source, propagatedwithin the plastic layer and incident upon the at least one furthermaterial layer back into the plastic layer by total internal reflection.57. The method of claim 55, comprising at least one step selected fromthe group consisting of: laminating two or more layers included in themultilayer structure together by pressure-sensitive adhesive, opticallyclear adhesive, solvent, ink, heat, pressure, or hot melt; additivelyproducing such as printing or 3D-printing at least one layer such as theplastic layer, a layer of the at least one reflective layer, a furthermaterial layer, a lightguide, a light outcoupling element, a diffuser,and/or other optically functional element; and providing a top-emittinglight source, on its side on the substrate film so that its contact padsface a direction transverse to the surface of the substrate film and arecontacted by conductive adhesive provided on the substrate filmelectrically joining the contact pads with the circuit design, theconductive adhesive being at least partially surrounded on the substratefilm by structural adhesive provided on the substrate film.
 58. Themethod of claim 55, comprising interconnecting a plurality of modulestogether, wherein each module comprises at least one of one or morelight sources of the at least one light source; at least a portion ofthe substrate film; and the circuit design; or at least a portion of alayer of the reflector design and/or at least a portion of the plasticlayer.
 59. The method of claim 55, wherein the plastic layer isconfigured with at least one hole to accommodate at least portion of theat least one light source.
 60. The method of claim 55, wherein theoptically transmissive layer is at least partially provided as apre-manufactured element initially separate from the first side of thesubstrate film, and arranged with at least portion of the reflectordesign prior to attaching the optically transmissive layer and substratefilm together either directly or via one or more intermediate layers.